Do you do regular video calls? Do you ever discuss anything aside from work? Even during a "work" discussion, do people make jokes, laugh, etc?
Do you have chat (slack) channels, and are they active? Does anyone ever spontaneously post something like "hey, anyone feel like talking about x that I'm trying to sort out?" Is chat pure business or do people ever discuss anything else?
These are all kind of leading questions, but the things that I think are key to making it work.